Scientist discovers method for reducing cheatgrass

A soil scientist working for the Agriculture Research Service has discovered a naturally occurring bacteria that could kill cheatgrass, or at least reduce the amount of the non-native species.

Cheatgrass out-competes native grasses by establishing a deep root system that grows early in the summer robbing the moisture that is needed by other species. It then dies in a thick mass that becomes fuel for large, intense wildfires. The invasion of cheatgrass over large swaths of the West is one of the reasons we have more large fires.

Below is an excerpt from an article in the New York Times about the work being done by Ann Kennedy of the Agricultural Research Service.

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“…Dr. Kennedy’s hunt for a cheatgrass killer has been nearly 30 years in the making. In 1986, she was investigating yellowed wheat in the Palouse country of eastern Washington State when she found some bacteria that appeared to inhibit the number of shoots that the wheat sent skyward, but not the wheat plant’s overall yield; the plant just made bigger kernels. Dr. Kennedy wondered if a bacterium could be used to frustrate weeds instead.

With help from undergraduates at Washington State University, where she is an adjunct professor, Dr. Kennedy tested 25,000 bacteria she took from nearby farm fields. Her goal was to find ones that satisfied a wish list of ideal attributes such as hindering cheatgrass while not affecting wheat. She likened the search to picky online dating.

The researcher finally settled on two strains of Pseudomonas fluorescens, a huge species of bacteria that is present throughout the natural world. Most of its strains perform beneficial functions in the environment.

In long-term field trials around the inland Pacific Northwest, including Hanford Reach National Monument in Washington State, Dr. Kennedy’s bacteria reduced the amount of cheatgrass in test plots by about half within three years of a single application.

“We get it down to near zero weeds within about five or six years,” Dr. Kennedy said, as other plants recover and grow more competitive. The bacteria also dispatch two other invasive plants, medusahead and jointed goatgrass. The latest findings will be published within the next year, she said…”